Described below is a method of controlling a linear power amplifier, particularly for use in mobile communication systems.
In a base station of a mobile communication system most energy is consumed by the power amplifier, therefore to make the base station more efficient, it is desirable to provide a power amplifier which uses less power. The supply voltage of the power amplifier is converted to an RF signal, but the amount of RF required varies over time. The cooling apparatus of the power amplifier is based on the maximum RF requirement, so it is also advantageous, if this can be reduced. For optimum efficiency, the supply voltage should track the signal, but in known methods the supply voltage is fixed and the power between the supply voltage and the signal voltage is lost because there are practical problems involved in varying the supply voltage at a high rate with current to track the signal voltage.